Systemic adverse events after botulinum neurotoxin A injections in children with cerebral palsy

Aim: To identify factors that increase the likelihood of systemic adverse events after botulinum neurotoxin A (BoNT-A) injections in children with cerebral palsy (CP). Method: A prospective observational study of patients attending a BoNT-A clinic at a tertiary paediatric hospital (2010–2014). Occurrences of systemic adverse events, defined as lower respiratory tract illnesses, generalized weakness, dysphagia, and death were determined at follow-up. The relationship between systemic adverse events and eight preinjection variables (age, Gross Motor Function Classification System [GMFCS] level, history of dysphagia, gastrostomy, aspiration pneumonia, recent history of illness, BoNT-A dose, and type of sedation) were examined using univariable and multivariable logistic regression with generalized estimating equations methods. Results: In total 591 children underwent 2219 injection episodes with follow-up in 2158 (97%) cases. Systemic adverse events were reported in 77 (3.6%) injection episodes. Univariable analysis suggested that GMFCS levels IV and V, a history of dysphagia, gastrostomy, aspiration pneumonia, and increasing BoNT-A dose increase the likelihood of systemic adverse events. In multivariable analysis, a history of dysphagia (odds ratio [OR] 3.42) and/or aspiration pneumonia (OR 2.31) remained associated with increased likelihood of systemic adverse events. Interpretation: A history of dysphagia and/or aspiration pneumonia are the factors that most increase the likelihood of systemic adverse events after BoNT-A. What this paper adds: Systemic adverse events occur in 3.6% of botulinum neurotoxin A (BoNT-A) injection episodes. Dysphagia and/or aspiration pneumonia are associated with increased likelihood of systemic adverse events. Multivariable models showed no evidence of association between Gross Motor Function Classification System and systemic adverse events. Multivariable models showed no evidence of association between BoNT-A dose and systemic adverse events.